1. Field of the Invention
This invention relates generally to easy opening containers of the kind having a tab which is flipped upwardly to open the container. The invention relates more particularly to an easy opening container having an improved easy opening tab arrangement which facilitates engagement of a finger under the tab to lift it.
2. PRIOR ART
Beverages are commonly sold in easy opening containers which are opened by lifting one end, referred to herein as its lifting end, of a lever-like tab pivotally attached between its ends to the normally upper end wall of the container. The opposite end of the tab, referred to as its free end, overlies a portion of the end wall forming a seal which effectively closes an opening in the wall through which the contents of the container, when opened, is dispensed. This seal is integrally joined to the surrounding container end wall along a major part of the seal perimeter by a narrow frangible juncture defining a frangible parting line between the seal and the surrounding end wall. Along the remainder of its perimeter, the seal is integrally joined to the surrounding end wall by a bendable juncture which is referred to herein as a hinge.
The container is opened by flipping up the lifting end of the tab. This action pivots the tab about its pivotal attachment to the container end wall in a direction to rotate the free end the tab downwardly against the container seal. The thrust of the free tab end against the seal first ruptures the container end wall along the frangible parting line, and then folds the seal downwardly about its hinge and into the container to form a dispensing opening in the end wall.
The prior art is replete with a vast assortment of easy opening containers of this kind. Examples of such containers are described in the following U.S. Pat. Nos.: 4,417,668; 4,433,792; 4,446,985; 4,576,304; 4,605,141; 4,720,022; 4,951,835. Of these, the DeMars et al U.S. Pat. No. 4,951,835 is perhaps the most pertinent to this invention because of certain of its features which are discussed below.
The existing easy opening containers are difficult to open because the tab is pivotally attached to the upper container end wall by a rivet or other means which normally holds the tab firmly against the upper container end wall. The tab is thus held firmly against the container end wall to facilitate fabrication of the containers and to permit stacking of the finished containers. Thus, during container manufacture, the upper container end walls are fabricated separately from the rest of the container body in the form of lids having a circular wall (upper container end wall) and a channel-like rim about the perimeter of the wall. The walls of these lids contain the seal-forming frangible and bendable hinge junctures and mount the easy opening tabs. During container fabrication, these lids are stacked and placed in automatic container fabricating machines which fold the rims of the lids downwardly over the ends of the cylindrical side walls of the container bodies and solder or otherwise seal the lids to these side walls in such a way as to form raised stacking beads or rims about the upper ends of the finished containers. Proper stacking of the lids during container fabrication and stacking of the finished containers requires that the easy opening tabs be normally lie firmly against the lid walls and upper end walls of the finished containers, as just mentioned. As a consequence, it is very difficult to get a finger under the lifting end of the tab to flip it up. For this reasons, many persons, particularly those with long finger nails, resort to the use of a slender implement of some kind to pry the tab up, at least enough to get a finger under the tab.
Attempts have been made to solve this problem in various ways. For example, the upper end walls of some containers have a shallow recess under the lifting end of the tab which provides a space between the tab and the floor of the recess to facilitate engagement of a finger under the tab. U.S. Pat. No. 4,951,835 provides such a space in a different way. The easy opening tab in this patent is rotatable about its pivotal attachment to the upper container end wall between a container stowage position and a container opening position. The container end wall has a cam over which the lifting end of the tab rides as it enters its container opening position, and which raises the lifting end of the tab upwardly away from the end wall to provide a space between the end wall and the lifting end.